Input checking, tooltips, options in combobox, conf parser, bugfixes

Input checking:
Modular, type-based input checking allows for quick implementation of new data types, which are automatically exposed and available to the lts_vars config parser.  Error messages are propagated to the status line in a sensical way.

Tooltips on main treeview:
When mousing over a row in the main treeview, tooltips now pop up if the variable is a standard/predefined one (defined in lts_vars.conf).  At least three babies and one very cute squirrel were sacrificed in the implementation of this.

Options in combobox:
Options combobox is now populated by all of the options in the lts_vars.conf file and by any in the current config.

Config Parsing:
The lts_vars.conf file contains meta info for variables, including type information, default values, and description/tooltips.
Config follows the format:
<variable>: <type name>, default <value> : <description>
..<variable> may be a range, defined by:
nameXX...nameYY
Example entries:
mystuff01...mystuff03: string, default gone fishing: mystuff variables contain my stuff
OTHERSTUFF: integer, default 9: amount of other stuff

Bugfixes:
various.  ..includes removal of .upper() calls on variable/option names, as changing the case of a variable makes it a different variable.